Platen control device



B. F. KUHNE PLATEN CONTROL DEVICE July 2, 1957 2 Sheets-Sheet l OriginaI Filed Feb. 2, 1953' INVENTORJ ,Br yan E Kuhne fiTTORNEX July 2, 1957 Original Filed Feb.

B. F. KUHNE PLATEN CONTROL DEVICE 2 Sheets-Sheet 2 INVENTOR, Bryan F. Kuhne ATTORNEY.

PLATEN CONTROL DEVICE Bryan F. Kuhne, Duarte, Califi, assignor to Clary Corporation, a corporation of California Uriginal application February 2, 1953, Serial No. 334,632,

new Patent No. 2,744,682, dated May 8, 1956. Divided and this application June 1, 1954, Serial No. 433,323

Claims. (Cl. 197-114) This invention relates to calculating and the like machines and has particular reference to machines capable of performing addition and the like operations and recording the factors and results of such calculations on a paper tape. However, it is to be understood that the invention may be applicable to other types of machines capable of recording data on paper.

Machines of the above type generally incorporate a rotatable paper supporting platen which is automatically and incrementally advanced as an incident to operation of the machine in order to permit listing of various values in sequence along the length of the tape. Usually the platen is also provided with a knob or the like whereby the same can be manually advanced to thread the tape through the machine or to provide a relatively large blank space for the purpose of entering identifying data or the like.

Such machines as, for example, that disclosed in Patent No. 2,583,810, issued to R. E. Boyden on January 29, 1952, incorporate a paper tear off bar located in close proximity to the platen so that a strip of tape having a list of tape figures printed thereon may be severed whenever desired. Following such a tear off operation it is frequently desirable to manually advance the paper to provide a blank space on the remaining portion of the tape and above the next list of figures. However, in actuating the platen rotating knob or other manual advancing device, the operator may inadverently rotate the platen in a retrograde direction and even though this movement may be relatively slight, it may be suflicient to retract the leading edge of the tape below the tear off bar. This would require rethreading of the tape past the tear off bar, and possibly past other parts of the machine, before commencing the succeeding printing operation. Although this problem could be solved by the simple expedient of providing a one-way control device associated with the platen to enforce rotation of the platen in a paper advancing direction only, it is frequently desirable to manually retract as well as advance the paper tape for different reasons.

The present invention overcomes the above difficulties by providing means which, after operation of the machine, requires a manual advancement of the platen and tape a sufficient amount before it can be retracted, thus insuring that the leading edge of the paper tape will not be inadvertently retracted below the tear off bar.

The manner in which the invention is carried out will be readily understood on reference to the following specification when read in conjunction with the accompanying drawings, wherein;

Fig. 1 is a plan view, with parts broken away, of an adding-listing machine embodying a preferred form of the present invention.

Fig. 2 is a sectional view through the printer and is taken substantially along the line 22 of Fig. 1.

Fig. 3 is a sectional view illustrating the mechanism for automatically advancing the platen as an incident to a machine operation.

atent The machine comprises a keyboard embodying a plurality of amount keys 11 ranging in value from one to nine. entries of amounts set up on the keyboard and to print this amount on a paper tape 12. This is accomplished by merely oscillating a drive handle 13.

The printer mechanism, generally indicated at 14, comprises a series of numeral type wheels, one of which is indicated at 15. Each wheel has a series of type arranged around the periphery thereof and progressing in value from 0 to 9.

Each numeral wheel 15 is rotatably mounted on an individual arm 16 loosely keyed on a printer control shaft 17. A spring 18 tensioned between each arm 16 and a suitable part of the frame (not shown) urges each arm and its wheel 15 toward printing contact with the tape, a printing ribbon 19 being interposed between the printing wheel and the tape to impress an image of the set type character on the tape.

Each printing wheel 15 has integral therewith a gear 20 permanently meshed with an idler 21 also rotatably mounted on the respective arm 16. Except during printing operations, the arms 16 are held against the action of their springs 18 by the shaft 17 which is effective to locate the arms in their positions illustrated in Fig. 2. In the latter positions, the idlers 21 are maintained in mesh with gears 22 forming part of the differential actuating mechanism for the machine.

The printer control shaft 17 is operatively connected to the handle 13 in a manner not shown, the arrangement being such that the shaft is rocked clockwise just before the operating handle reaches the forward extremity of its stroke, and just after the gears 22 have differentially advanced the type wheels 15 to their proper positions, permittting the springs 18 to swing their respective type arms 16 clockwise to effect the printing operation.

The paper tape 12 is guided into intimate contact with the platen 23 and is advanced one step or increment during the latter half of the machine cycle. For this purpose, the tape, as it is passed from a supply roll, partially indicated at 24, is guided around a feed roller 25 and into engagement with the platen. The tape thereafter passes between a second feed roller 26 and the platen, past a printing station P and thence under a tear off bar 27, see also Fig. 1, extending across the path of the tape.

In order to advance the paper tape 12 as an incident to each operation of the machine, a ratchet wheel 28 is suitably secured to the shaft of the platen and is operable by a pawl 29. The latter is pivoted at 146 to a cam follower 147 and is normally urged upwardly and to the left in Fig. 3 by a spring 148. The latter is tensioned between the lower end of pawl 29 and a spacing control arm 150 which, for the purpose of the present disclosure, may be considered as mounted stationary on the machine frame.

The cam follower 147 is pivoted on a shaft 62 and is provided with a roller 152 which rides in a camming slot formed in a box cam 153 keyed on a drive shaft 35. The latter is operatively connected to the handle 13 and is rocked counter-clockwise during advancement of the handle and thereafter returned to its home position during the return of the handle.

When the machine has completed its cycle the parts The machine is normally set to effect additive assume their positions shown in Fig. 3 wherein a laterally extending finger 30 at the top of pawl 29 is retained in engagement with the ratchet wheel 28, thereby preventing any retrograde rotation thereof; As the handle is operated through its stroke to cycle the machine, the pawl 29 is moved through the medium of cam 153 to its upper dot and dash line position 29a. Upon returning downward during the latter half of the cycle, the finger 39 engages a tooth of the ratchet wheel and advances the same, terminating in the position shown in Figs. 3 and 4.

In order to yieldably hold the platen in different rotated positions, a pawl 154, pivoted on a frame pin 155, is urged clockwise by a spring 156 to hold the roller 157 thereon in engagement with two teeth of the ratchet wheel 28.

The arm 150 controls the extent of advancement'of the platen by the pawl 29 and for this purpose it is provided with a guide pin 158 which lies directly in front of and guides the pawl 29. In this position of the parts the pawl is effective to engage and advance the ratchet one increment or one tooth space. only during its subsequent stroke, thereby likewise advancing the paper tape 12.

Means are provided for enabling manual advancement or retraction of the platen and for this purpose a rotary knob 160 (Fig. l) is suitably attached (in a manner not shown) to the platen 23 and protrudes through an opening 162 in the machine case 163.

As such platens may be manually rotated in either direction it frequently happens that knobs similar to the knob 160 are accidently twirled in the wrong direction following a tear oif operation, wherein the printed portion of the tape is severed from the remainder of the tape by tearing the same over the tear off bar. In such case, the tape would retract below the tear off bar, like bar 27, and possibly past other operating parts of the machine, thus requiring rethreading. In order to overcome this difiiculty, means are provided in the present machine for normally preventing retrograde rotation of the platen by the knob 160 following an automatic advancement thereof by the pawl 30, while permitting such retrograde rotation by the knob 160 only after the latter has advanced the platen a certain amount in a paper feeding direction. 163 is provided, being pivoted on the aforementioned frame pin 155 and urged clockwise by a spring 164 to normally maintain a retaining nose 165 thereof in engagement with the actuating finger 30 of the pawl 29.

The nose 165 has a shoulder 166 thereon located just inside the periphery of the teeth of the ratchet wheel 28 when the parts are in their relative positions shown in Fig. 4. Accordingly, at the completion of a machine cycle the pawl 29 will assume the position shown in Fig. 4, being located in engagement with one of the teeth of the ratchet wheel and overlying the nose 165, thus holding the latch 163 rocked in a counter-clockwise direction. In this position, the pawl 29 will prevent retrograde (counter-clockwise) rotation of the platen but will not impede forward (clockwise) rotation thereof by the twirler knob 160. However, any forward rotation of the platen by the twirler knob will cause the next succeeding tooth of the ratchet wheel to cam the pawl 29 clockwise about its pivot 146 against the action of the spring 148 and past the shoulder 166. Spring 164 will then become effective to rock the latch 163 clockwise about its pivot 155, causing the shoulder 166 to pick up, the finger 3.0 and thus hold the pawl 29 clear of the ratchet wheel 28 as shown in Fig. 5. I Thereafter, the platen may be manually rotated in either direction to any desired extent. 7

In the machine cycle subseqeunt to positioning of the parts intheir positions shown in Fig. 5, the pawl. 29

will rise away from the shoulder 166 toward its position indicated at 29a (Fig. 3),- whereupon the spring l 48 will become effective to return the pawl into it's normal path For this purpose, a retainer or latch of movement shown in Fig. 3. As the pawl 29 rises, the latch 163 will be retained by its spring 164 in its position shown in Fig. 5 against a frame pin 167. However, as the pawl returns downward its finger 30 will again engage the latch, rocking the same back to its position shown in Fig. 4.

Although I have described my invention in detail and have therefore used certain terms and language therein, it is to be understood that the present invention is illustrative rather than restrictive and that changes and modifications may be made without departing from the spirit or scope of the invention as set forth in the claims appended hereto.

Having thus described the invention, what I desire to secure by United States Letters Patent is:

1. In a calculating machine having a rotatable platen, means for maintaining a paper strip in contact with said platen, a ratchet carried by said platen, and a pawl for advancing said ratchet, the combination of means for reciprocating said pawl, said means normally holding said pawl at the forward extremity of its travel, means normally maintaining said pawl in engagement with a tooth of said ratchet whereby to prevent retrograde rotation of said platen, a succeeding tooth of said ratchet being etfective to move said pawl out of engagement with said ratchet upon forward rotation of said platen relative to said pawl, and means responsive to said outward movement of said pawl for maintaining said pawl out of engagement with said ratchet.

2. In a calculating machine having a rotatable platen, means for maintaining a paper strip in contact with said platen, a ratchet carried by said platen, and a pawl for advancing said ratchet, the combination of means responsive to operation of said machine for reciprocating said pawl, said pawl normally resting at the forward extremity of its travel, spring means normally maintaining said pawl in engagement with a tooth of said ratchet whereby to prevent retrograde rotation of said platen, a succeeding tooth of said ratchet being adapted to move said pawl out of engagement with said ratchet upon forward rotation of said platen relative to said pawl, a latch responsive to said outward movement of said pawl for maintaining said pawl out of engagement with said ratchet, and means responsive to subsequent reciprocatory movement of said pawl for rendering said latch ineffective.

3. In a calculating machine having a rotatable platen, means for maintaining a paper strip in contact with said platen, a ratchet carried by said platen, and a pawl for advancing said ratchet, the combination of means for reciprocating said pawl, said means normally holding said pawl at the forward extremity of its travel, means normally maintaining said pawl in engagement with a tooth of said ratchet whereby to prevent retrograde rotation of said platen, a succeeding tooth of said ratchet being effective to cam said pawl out of engagement with said ratchet upon forward movement of said ratchet relative to said pawl, and a latch operable in response to said outward movement of said pawl to hold said pawl out of engagement with said ratchet.

4. In a calculating machine having a rotatable platen, means for maintaining a paper strip in contact with said platen, a ratchet carried by said platen, and a pawl for advancing said ratchet, the combination of means responsive to operation of said machine for reciprocating said pawl, said pawl normally resting at the forward extremity of its travel, a spring normally maintaining said pawl in engagement with a tooth of said ratchet whereby to prevent retrograde rotation of said platen, a tooth of said ratchet being adapted to move said pawl out of engagement with said ratchet upon forward rotation of said platen relative to said pawl, a latch, a spring effective to cause said latch to latch said pawl out of engagement with said ratchet upon movement of said pawl by a succeeding tooth, and means effective to render said latch 5 ineitective upon subsequent movement of said pawl through its travel.

5. In a calculating machine having a rotatable platen, means for maintaining a paper strip in contact with said platen, a ratchet carrried by said platen, and a pawl engageable with said ratchet for advancing said platen, the combination of means for reciprocating said pawl, spring means normally maintaining said pawl in engagement with a tooth of said ratchet whereby to prevent retrograde rotation of said platen, the teeth of said ratchet being effective to cam said pawl out of engagement therewith upon forward rotation of said platen relative to said References Cited in the file of this patent UNITED STATES PATENTS 654,181 Rinsche July 24, 1900 1,192,629 Hawley July 25, 1916 2,534,461 Lorenz et a1 Dec. 19, 1950 

